import java.util.Scanner;

/**
 * 判断一个数是否是素数 
 * 去掉偶数，从3到X-1，每次加2，测试是否可以被整除
 * @author zk
 */
public class JudgePrime {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int x = in.nextInt();
		in.close();
		boolean isPrime = true;
		if (x == 1 || x % 2 == 0 && x != 2) {
			isPrime = false;
		}
		for (int i = 3; i < x; i+=2) {
			if (x % i == 0) {
				isPrime = false;
				break;
			}
		}
		if (isPrime) {
			System.out.println(x + "是素數");
		} else {
			System.out.println(x + "不是素數");
		}

	}

}
